DESCRIPTION: (adapted from the applicant?s abstract): Temporomandibular disorders (TMD) are common problems in the general population. The Research Diagnostic Criteria (RDC) for TMD were developed to establish specific operationalized examination procedures and diagnostic criteria for 8 Axis I biomedical diagnoses of TMD, as well as Axis II biobehavioral assessment procedures. Procedural reliability testing has been established for the RDC Axis I examination items, but full acceptance of the RDC requires confirmation of the temporal stability, validity, generalizability and clinical utility of the examination items, biomedical diagnoses, biobehavioral assessments, and general protocol. In order to accomplish these overall goals, a multi-center project is proposed that will first reassess at the University of Minnesota the reliability of 6 examiners (2 examiners each from 3 participating universities) to collect clinical Axis I examination data using the RDC operational definitions. In a second step, reliable blinded examiners will collect clinical examination data and formulate RDC diagnoses, which will be compared to criterion diagnoses made by an expert imaging. New clinical exam items will also be assessed. Subject to expert consensus, they will be added to yield a final exam protocol that will include all current RDC examination items as well as the new items. With this new protocol, the 6 examiners will continue examining normal and TMD subjects at their respective centers in order to test the temporal stability and diagnostic validity of the new and existing examination items, patient history items, and TMJ imaging by plain film and MRI. Discriminant analyses and decision tree analyses will be used to determine the best diagnostic algorithms for rendering RDC diagnoses. Masticatory muscle biopsies and TMJ synovial fluid will be collected from subjects at the University of Minnesota to evaluate biological markers for their role as potential mediators underlying the biomedical diagnoses. Simultaneously, Axis II biobehavioral assessment procedures will be tested for temporal reliability, compared with other accepted self-report instruments for concurrent validity, and, at two centers, evaluated for criterion validity against highly structured psychiatric interviews. The clinical and health services utility of adding Axis II biobehavioral assessments, imaging and biopsy results to Axis I clinical examination findings will be appraised. Advancement in our understanding of the prevalence, etiologies, natural progression, and treatment of TMD is dependent on having reliable and valid diagnostic criteria for these disorders.